490 SPECIES OF CAPJKOMYS suggests a Water-Sat of large size (it has been exhibited in shows as a phenomenal product of London sewers!); the tail is nearly as long as the body. The ears are small. The limbs are short. The tail is naked. The hind-feet are webbed, but not so much so as in Hydromys, A small thumb is present. The animal has thirteen pairs of ribs; the molars are four in each jaw. The large intestine is more than three times the length of the small, and the caecum. is, as in the last genus, relatively short. Oapromys is a genus -1 which is remarkable on account of its restricted distribution. It is found only in the islands of Cuba and Jamaica. There are four species, of which C. melanurus is a dark brown-coloured animal with a blacker tail, nearly as large as a [Rabbit. The native name of this Kodent is " hutia," It is also remarkable for having a stomach more complicated than is the rule among the mammals of this group. The organ is divided by two constrictions into three compartments. In G. pilorides the liver is occasionally divided up in an extra- ordinary fashion into small lobules. Oapromys has the large number of sixteen dorsal vertebrae. Faitt. 2. Ctenodactylidae.—For these African genera it seems admissible to form a distinct family., though Thomas, and Flower and Lydekker, only allow to the genera Ctenodactylus, Pectinator, and Massoutiera, sub-family rank. On the other hand, Tullberg removed these genera entirely from the Hystricornorph section and placed them, as a section of the sub-tribe Myomorphi of the tribe Sciurognathi. It was chiefly the form of the mandible which led to this placing, for in these Eodents, as in all Squirrel- and Bat-like Rodents, and unlike what is found in the Hystrici- form genera, the angular process of the mandible is not bent sideways. The genus Ctenodctctylus derives its name from the peculiar strong bristles which form a comb-like structure upon the hind- feet and hide the claws; these are stated to be for the purpose of dressing the fur. The Oundi of North Africa, G. gundi, has a length of 190 mm., with a short tail of 17 mm. The ears are only moderate in size. The dental formula of the molars is -f. The incisors are white. The feet have four digits, and the hind- limbs are the longer. The large intestine is distinctly longer than, the small intestine. 1 See Dobson, Proc. Zool. Soc. 1884, p. 233.